Resonator silencer



July 27, 1943. E E WILSON RESONATOR SILENCER Original Invcntor H attorneys 91196; July 25 1930 I8 secured over its ends.

' Patented July 27, 1943 RESONATOR SILENOER Ernest E. Wilson, near Milford, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application July 25, 1930, Serial No. 470,700. Divided and this application June 15, 1940, Serial No. 340,661

22 Claims.

This invention has to dov with resonator silencers.

In general, the objects of the invention are the same as those set forth in my application Serial No. 470,700, filed July 25, 1930, of which this application is a division.

In particular, this invention has to do with the mode of connecting chambers of a multiplechamber resonator silencer to the duct in which occur the sound waves which are to be attenuated by the silencer and has for its principal object to provide a resonator silencer with a plurality of chambers connected in a novel and advantageous manner to the duct in which occur the sound waves which are to be attenuated by the silencer.

For a better understanding of the nature and objects of the invention with whichthis application is concernedfreference is made to the following specification !n which there are described the embodiments of the invention which are illustrated in the accompanying drawing.

In the accompanying drawing:

Figure 1 is a side elevation of an interna1 combustion engine in whose intake system there are installed resonator silencers in accordance with this invention.

Figure 2 is a central longitudinal section through the silencer installed on the intake manifold of the engine illustrated in Figure 1.

Figure 3 is a central longitudinal section through the silencer installed on the intake tube of the carburetor of the engine illustrated in Figure 1.

In the drawing, the reference character it! indicates an internal combustion engine with an intake system which includes -a carburetor ll and an intake manifold l2 through which combustible mixture travels from the carburetor to the cylinders of the engine. To the intake manifold l2 directly above the riser and to the air intake tube l3 of the carburetor, there are connected resonator silencers M and IS in accordance with this invention.

The silencer M which is shown in Figures 1 and 2 of the drawing of this application is that which is shown in Figures 1 and 3 of the drawing of my application Serial No. 470,700. It includes a cylindrical shell 16 with heads 57 and Through a central opening in the head l8, there extends into the compartment defined by the shell 16 and the heads I? and 88 a tube l9 which is secured circumferentially at a point between its ends to the head 18 around the central opening in it. The compartment defined by the shell to and the heads I! and H3 is divided lengthwise into resonance chambers 20 and 2! by a transverse partition 22 which has a central opening in it and whose outer edge is secured circumferentially to the shell "5. To the edge of the partition 22 which encircles the central opening in it, there is circumferentially secured one end of a tube 23 whose other end extends into the inner end of the tube I9. The tube 23 is of sufliciently smaller diameter than the tube l9 that the over lapping ends of the tubes are separated by an annular aperture 24.

The silencer I5 which is shown in Figures 1 and 3 of the drawing of this application is the modification of the silencer shown in Figures 1 and 2 of the drawing of this application and Figures 1 and 3 of the drawing of my application Serial No. 470,700 which is described in the paragraph beginning in line 3 of page 38 of the specification of my application Serial No. 470,700. It includes a cylindrical shell 25 with heads 28 and 21 secured over its opposite ends. Through a central opening in the head 27,- there extends into the interior of the shell 25 a tube 28 which is secured circumferentially at a point between its ends to the head 21 around the central opening in it. In a central opening in the head 20, there is secured circumferentially one end of a tube 29 which extends into the interior of the shell 25 and whose other end extends into the inner end of the tube 20. The tube 29 is sufficiently smaller in diameter than the tube 28 that the overlapping ends of the tubes are separated by an annular aperture 30. The compartment defined by the shell 25, the heads 20 and 27 and the tubes 29 and 20 which define the duct through which gases and sound waves travel through the silencer I5 is divided into resonance chambers 35 and 32 by a transverse annular partition 33 whose outer edge is secured circumferentially to the shell 25 and whose inner edge encircles but is radially spaced throughout its circumference from the tube 29. In the central opening in the partition 33, there is secured circumferentially one end of a tube 34 whose other end extends into the annular aperture 30 between the overlapping ends of the tubes 29 and 28 to a point short of that to which the tube 29 extends. The tube 34 is suificiently larger in diameter than the tube 20 and sufiiciently smaller in diameter than the tube 28 that the overlapping portions of the tubes are separated by annular apertures 35 and 30 through which and the portion of the annular aperture 30 into which the tube 34 does not extend the resonance chambers 31 and 32 communicate with the duct defined by the tubes 29 and 28.

The silencer I4 illustrated in Figures 1 and 2 of the drawing was designed, as I have indicated and shown in the drawing, for installation on an internal combustion engine with the outer end of the tube 59 secured in an orifice in the intake manifold of the engine, preferably directly above the riser, so that the resonance chambers 20 and 2| communicate with the interior of the manifold through the tubes 23 and I9 and the annular aperture 24 and the tube l9,respective1y.' The silencer l shown in Figures 1 and 3 was, on the other hand, as I have also indicated and shown in the drawing, designed for installation on an internal combustion engine with the outer end of the tube 28 secured in the air intake tube of the carburetor so that the duct defined by the tubes 29 and 28 constitutes an. extension of the airintake tube of the carburetor. silencers are so installed andthe engine is operating the suction created by the cylinders of the engine on their suction strokes will draw air through the duct defined by the tubes 29 and 28 of the silencer I5, thecarburetor H and the intake manifold 12 into the-cylinders of the engine.

The resonance chambers of the silencer shown in Figures 1 and 2 of the drawing and the tubes and annular aperture which connect them to the interior of the intake manifold and the resonance chambers of the silencer shown in Figures 1 and 3 of the drawing and the annular apertureswhich. connect them to the-duct defined by the tubes 29 and 28, of course, constitute resonators. These resonators are so proportioned and dimensioned ,in accordance with the disclosure of my applicatiori Serial No. 470,700 that they respond to and attenuate by resonance the objectionable sound waves which are ordinarily transmitted through the intake manifold and carburetor of the engine to the atmosphere and thus eliminate the intake noises of the engine.

The showing of the two silencers M and IE on the same engine is largely a matter of convenience in illustration. It is not necessary to use both of them to efiectually silence the intake noises of an engine. However, it may be well to point out that when a given resonator is connected to the intake system of an engine on the engine side of its carburetor-its eifect on the intake noises of the engine is somewhat less but its efiect on the power of the engine mentioned in my application Serial No. 470,700 is somewhat greater than when the resonator connected to the intake system of the engine on the atmospheric side of its carburetor and, consequently, there may be instances in which it is advantageous to install resonator silencers in both locations on the same engine.

It is, of course,-to be understood that resonator silencers in accordance with this invention are not limited to use on the intake systems of internal combustion engines but may also be employed on the exhaust systems of such engines and elsewhere that. silencers are required.

I claim:

1. In an internal combustion engine, a carburetor, a duct which connects the carburetor with a cylinder of the engine and through which gases and sound waves travel during operation of the engine, a resonator which is arranged as a branch of the duct and is so tuned that it responds to and attenuates by resonance the sound waves ofa preselected frequency which travel through the duct, the resonator including .a chamber which ommunicates with the duct on the engine side oi the carburetor.

2. In, n internal combustion engine, a duct which communicates with a cylinder of the engine and through which gases and sound waves travel during operation of the engine, resonators which are arranged as branches of the duct and are so tuned that they respond to and attenuate by resonanc sound waves of a preselected frequency whichttravel through the duct, each res- When the onator including a chamber and an orifice through which the chamber is connected to the duct independently of the chamber included in the other resonator.

3. The combination, with a duct through which sound waves travel, of a sound wave attenuator which includes a chamber, an orifice through which the chamber communicates with the duct, and nother chamber which communicates with the duct through the specified orific independently of the first-specified chamber.

4. The combination, with a duct or other enclosure within which sound waves occur, of a side branch which includes a chamber and a passage through which the chamber communicates with the enclosure and a chamber and a passage through which the second-mentioned chamber communicates with the first-mentioned passage independently of the first-mentioned chamber.

5. The combination, with a duct through which sound waves travel, of a sound wave attenuator which includes a shell, a partition which divides the shell into two chambers, a tube which opens into the duct and into one of the chambers, and a tube which opens into the other of the chambers and extends and opens into the first-specified tube.

.6. In a silencer, two partly telescoped, radially spaced tubular structures which define a duct, a shell which defines a compartment which encircles the duct, a partition which is secured to the shell and divides the compartment into two chambers of which one communicates with the duct through the aperture between the tubular structures, and an orifice in one of the tubular structures through which the other of the chambers communicates with the duct.

7. In a silencer, a duct in which there are included two partly telescoped, radially spaced tucluded two partly telescoped, radially spaced tubular structures through which gases and sound waves may travel, walls which with the tubular structures define a compartment which encircles the duct, a wall which is joined to the outer-of the tubular structures and subdivides the compartment into two chambers of which one communicates with the ductthrough the aperture between the tubular structures, and an orifice in th outer of the tubular structures through which the other of the chambers communicates with the duct.

9. In a silencer, a duct in which there are included two partly telescoped, radially spaced tubular structures, a wall which encircles and is radially spaced from a portion of the duct, walls which with the tubular structures and the first specified wall define a compartment, a wall which is secured to the outer of the tubular structures and subdivides the compartment longitudinally into two chambers of which one communicates with the duct through the space between the tubular structures, and an aperture in a portion of the outer of the tubular structures which is which defines a compartment which encircles the duct, a tube which encircles and is radially spaced from a portion of one of the first-specified tubes, and a partition which is secured to the shell and the third-specified tube and divides the compartment into two chambers of which one communicates with the duct through the aperture between the first-specifiedtubes and the other communicates with the duct through the aperture between the third-specified tube and that of the firstspecified tubes of which it encircles a portion.

. 11. In a silencer, a duct which consists of two Partly telescoped, radially spaced tubular elements, a wall which encircles and is radially spaced from a portion of the duct, walls which with the tubular elements and the first-specified wall define a compartment, a tubular element which encircles and is radially spaced from a portion of the inner of the first-specified tubular elements, and a wall which is secured to the third-specified tubular element and subdivides the compartment longitudinally into two chambers.

12. In a silencer, a duct in which there are included two aligned tubular elements, a wall which encircles and is radially spaced from a portion of the duct, walls which with the tubular elements and the first-specified wall define a compartment, a tubular element which en= circles one end of one and is encircled by the adjacent end of the other of the first-specified tubular elements, and a wall which is secured to the third-specified tubular element and subdivides the compartment longitudinally into two chambers.

13. In a silencer, a duct which consists of two partly telescoped, radially spaced tubular elements, a wall which encircles and is radially spaced from a portion of the duct, walls which with the tubular elements and the first-specified Wall define a compartment, a tubular element which encircles a portion of the inner and extends into the outer'of the first-specified tubular elements to a point short of that to which the inner of the first-specified tubular elements extends, and a wall which is secured to the third-specified tubular element and subdivides the compartment longitudinally into two channbers.

14. In a silencer, a shell, a duct which extends through the shell and with it defines a compartment which encircles the duct, a partition which subdivides the compartment lengthwise into two chambers, the duct including two tubelike members ofrwhlch one extends into and is radially spaced from the other to define'with it an aperture through which one of the chambers communicates with the duct, and an aperture in one of the tube-like members through which the other of the chambers communicates with the duct.

15. The combination, with a duct through which sound waves travel, of a sound wave-attenuator which includes a chamber, a constrictive orifice through which the chamber communicates with the duct, and another chamber which is enlarged with respect to the specified orifice and through it communicates with the duct independently of the first specified chamber.

16. The combination, with a duct or other enclosure within which sound waves occur, of a side branch which includes a chamber and a constrictive passage through which the chamber communicates with the enclosure and a chamber and a constrictive passage through which the second mentioned chamber communicates with the first mentioned passage independently of the first mentioned chamber.

17. The combination, with a duct through which sound waves travel, of a sound wave attenuator which includes a resonator which is so tuned that it resonates to and thus attenuates sound waves of a preselected frequency which travel through the duct, the resonator including a chamber which constrictively communicates with the duct as a side branch, and another chamber which communicates with the duct as a side branch and is connected thereto independently of the first specified chamber by a con= strictive conduit which extends through the latter.

18. The combination, with a duct through which sound waves travel, of a sound wave attenuator which includes a resonator which is so tuned that it resonates to and thus attenuates sound waves or a preselected frequency which travel through the duct, the resonator including 1 chambers which independently of each other constrictively communicate with the duct as side branches at the same point at the length of the duo 19, The combination, with a duct through which sound waves travel, of a sound wave attenuator which includes a shell, a partition which divides the shell into two chambers, a constrictive tube which opens into the duct and into one of the chambers, and a constrictive tube which opens into the other of the chambers and extends and opens into the first specified tube.

20. In a silencer, a duct, awall which encircles and is radially spaced from a portion of the duct, walls which with the duct and the first specified wall define a compartment, a wall which subdivides the compartment into two chambers, and I constrictive passages which connect the chambers to the duct independently of each other at the same distance from the end of the duct, the chambers and the constrictive passages which connect them to the duct being so proportioned and dimensioned that they resonate to and thus attenuate sound waves or a preselected frequency which travel through the duct.

21 In a silencer, a duct through which gases may travel; a chamber, a duct through which the chamber communicates with the first-specified duct, and another chamber which communicates with the first-specified duct through the second-specified duct independently of the firstspecified chamber.

22. The combinatiornwith a duct or other enclosure within which sound waves occur, of a side branch which includes a chamber and a passage through which the chamber communicates with the enclosure and a chamber and a passage through which the second-mentioned chamber communicates with the first-mentioned passage and is so proportioned and dimensioned that it responds to'and attenuates by resonance objectionable sound waves which occur within the enclosure.

ERNEST E. WILSON. 

